Measuring round trip time in a mobile communication network

Abstract

Apparatuses, methods, and systems are disclosed for measuring RTT. One apparatus includes a processor and a transceiver that communicates with a mobile core network via an interworking function. The processor transmits a first request to establish a data connection between the apparatus and the mobile core network, wherein the first request includes a first indicator that the apparatus supports round trip time (“RTT”) measurements, the RTT measurements calculated using messages transmitted via the data connection and using an encapsulation header. The processor receives a first message from the interworking function and transmits a second message to the interworking function, wherein the first message includes a first encapsulation header comprising an echo request indication wherein the second message includes a second encapsulation header including an echo response indication.

The invention claimed is: 
     
       1. An interworking apparatus comprising:
 a first interface that communicates with control-plane functions in a mobile core network; 
 a second interface that communicates with a remote unit over a non-3GPP access network, wherein the interworking apparatus is a gateway between the non-3GPP access network and the mobile core network; and 
 a processor that:
 receives a request via the first interface to establish access resources for enabling data communication between the remote unit and the mobile core network via a data connection, wherein the data connection supports a plurality of quality of service (“QoS”) flows, and the request includes a first indicator that requests round trip time (“RTT”) measurements using a first QoS flow of the data connection; 
 transmits a first message to the remote unit via the second interface and using the first QoS flow of the data connection, wherein the first message includes a first encapsulation header that comprises an echo request indication, wherein the first encapsulation header is a packet header that complies with a General Routing Encapsulation (“GRE”) protocol; 
 receives a second message via the second interface, wherein the second message includes a second encapsulation header that comprises an echo response indication, wherein the second encapsulation header is a packet header that complies with the GRE protocol; and 
 measures a RTT for the first QoS flow of the data connection using the echo response indication. 
 
 
     
     
       2. The apparatus of  claim 1 , wherein the processor further determines whether an average RTT meets a reporting condition and transmits a first notification via the first interface in response to the average RTT meeting the reporting condition, wherein the average RTT is based on the measured RTT. 
     
     
       3. The apparatus of  claim 2 , wherein the processor determines whether an average RTT meets a reporting condition by evaluating one or more reporting conditions included in the first indicator. 
     
     
       4. The apparatus of  claim 1 , wherein the processor further forwards, via the second interface, a second notification received via the first interface, wherein the second notification comprises an average RTT. 
     
     
       5. The apparatus of  claim 1 , further comprising a third interface that communicates with a user-plane function in the mobile core network, wherein the first message contains a Protocol Data Unit (“PDU”) received via the third interface. 
     
     
       6. The apparatus of  claim 5 , wherein the processor further determines whether an average RTT meets a reporting condition and transmits a notification via the third interface in response to the average RTT meeting the reporting condition, wherein the average RTT is based on the measured RTT. 
     
     
       7. The apparatus of  claim 1 , wherein the first message contains a dummy Protocol Data Unit (“PDU”), wherein the remote unit sends the second message while ignoring the dummy PDU. 
     
     
       8. The apparatus of  claim 1 , wherein the first message includes a GRE header comprising the echo request indication in response to receiving the first indicator, and wherein the echo request indication comprises a set of bits in the GRE header. 
     
     
       9. The apparatus of  claim 8 , wherein the echo request indication uses a first value to indicate that a packet payload associated with the GRE header contains a Protocol Data Unit (“PDU”) received from a user-plane function in the mobile core network and uses a second value to indicate that the packet payload contains a dummy PDU that is to be ignored by the remote unit. 
     
     
       10. The apparatus of  claim 9 , wherein the echo response indication comprises a set of bits in the GRE header, wherein the echo response indication uses a third value to acknowledge the echo request. 
     
     
       11. The apparatus of  claim 1 , wherein the processor further:
 receives a third message from the remote unit via the second interface by using the first QoS flow of the data connection, wherein the third message includes the first encapsulation header comprising a second echo request indication; and 
 transmits a fourth message via the second interface, wherein the fourth message includes the second encapsulation header comprising a second echo response indication, wherein the remote unit measures the RTT for the first QoS flow of the data connection using the echo response indication. 
 
     
     
       12. The apparatus of  claim 11 , wherein the third message contains a dummy Protocol Data Unit (“PDU”) encapsulated by the first encapsulation header, wherein the processor sends the fourth message while ignoring the dummy PDU. 
     
     
       13. The apparatus of  claim 11 , wherein the third message contains an uplink PDU encapsulated by the first encapsulation header, wherein the processor sends the fourth message and forwards the uplink PDU to the mobile core network. 
     
     
       14. The apparatus of  claim 1 , wherein the processor further receives a measurement parameter via the first interface, wherein the measurement parameter indicates a frequency for measuring RTT. 
     
     
       15. A method of an interworking function, the method comprising:
 supporting a first interface that communicates with control-plane functions in a mobile core network and a second interface that communicates with a remote unit over a non-3GPP access network, wherein the interworking function is a gateway between the non-3GPP access network and the mobile core network; 
 receiving a request via the first interface to establish access resources for enabling data communication between the remote unit and the mobile core network via a data connection, wherein the data connection supports a plurality of quality of service (“QoS”) flows, and the request includes a first indicator that requests round trip time (“RTT”) measurements using a first QoS flow of the data connection; 
 transmitting a first message to the remote unit via the second interface and using the first QoS flow of the data connection, wherein the first message includes a first encapsulation header that comprises an echo request indication, wherein the first encapsulation header is a packet header that complies with a General Routing Encapsulation (“GRE”) protocol; 
 receiving a second message via the second interface, wherein the second message includes a second encapsulation header that comprises an echo response indication, wherein the second encapsulation header is a packet header that complies with the GRE protocol; and 
 measuring a RTT for the first QoS flow of the data connection using the echo response indication. 
 
     
     
       16. The method of  claim 15 , further comprising:
 supporting a third interface that communicates with a user-plane function in the mobile core network; 
 determining whether an average RTT meets a reporting condition; and 
 transmitting a notification via the third interface in response to the average RTT meeting the reporting condition, wherein the average RTT is based on the measured RTT. 
 
     
     
       17. The method of  claim 15 , wherein the first message includes a GRE header comprising the echo request indication in response to receiving the first indicator. 
     
     
       18. The method of  claim 15 , further comprising receiving a measurement parameter via the first interface, wherein the measurement parameter indicates a frequency for measuring RTT. 
     
     
       19. The method of  claim 17 , wherein the first message includes a GRE header comprising the echo request indication in response to receiving the first indicator, and wherein the echo request indication comprises a set of bits in the GRE header. 
     
     
       20. The method of  claim 19 , wherein the echo request indication uses a first value to indicate that a packet payload associated with the GRE header contains a Protocol Data Unit (“PDU”) received from a user-plane function in the mobile core network and uses a second value to indicate that the packet payload contains a dummy PDU that is to be ignored by the remote unit.